It may seem strange to even be thinking about the potential for snow to fall after the intensity of warm air we saw earlier in the month, but this is the weather for you!This is a particularly difficult situation to assess given the fact that ground temperatures are warm, however the precipitation/snow could be falling at a fairly heavy rate which would greatly aid in the accumulation process, as well as evaporational cooling.However, I still think that air temperatures 2M above the ground (know as surface temperatures) will be too warm during the day, and ground temperatures will be too warm for anything significant to accumulate. However, this isn't to say that tomorrow evening's and Saturday morning's driving will be easy. If the snow falls at some of the rates currently anticipated by some models, visibility could be greatly reduced Friday evening and into the overnight period into early Saturday. I expect the heaviest precipitation to fall between 5-10 p.m. Friday evening. I emphasize precipitation, as I am still uncertain as to which areas will receive snow, which rain, which ice pellets and which a wonderful mixture.Unfortunately, two of the short-range higher resolution numerical models are currently down/not updating which would be very useful right now in forecasting, but I'll do my best.Forecast:I expect precipitation to start as rain in most places in southern Ontario tomorrow afternoon, but temperatures should begin to drop fairly significant once precipitation starts. It should transition over to snow first in the Kitchener-Waterloo region, and then in the GTA and Toronto (north of downtown). Wet snow should then continue through the evening Friday, and taper off early morning Saturday. Kingston will likely not receive much in the way of precipitation if anything at all, and places like London, Sarnia and Windsor will likely receive mostly rain. I expect a bit more of a mix possibly in the Niagara region, particularly southern portions, after the initial wave of rain.Amounts:Toronto downtown: 2-5cm fall (trace-3cm accumulates)Toronto north of downtown(about St.Clair I'd say for this one) to Steeles: 4-8cm fall (2-5cm accumulates)Hamilton: 5-10cm fall (3-6cm accumulates)Niagara: 4-8cm fall (2-5cm accumulates)Burlington: 3-8cm fall ( 2-5cm accumulates)Newmarket: 5-10cm fall (3-8cm accumulates)'Barrie: 6-12cm fall (4-8cm accumulates)

Depending on how things change over the next 12 hours or so, I may update this forecast sometime tomorrow afternoon.Otherwise, drive safely everyone!

These thunderstorms are really powerful! Frequent lightning and some heavy thunder with torrential rains. I'd say these are even approaching severe limits down here judging by how hard the rain is coming down.

---------------------------------------------------------------------==discussion==A disturbance from the American Midwest will track just south of LakeErie this evening giving a variety of inclement weather to SouthernOntario.

A light snowfall is expected north of a line from Central Lake Huron to Toronto with a mixed bag of rain and snow to the south.Over Extreme Southwestern Ontario showers and thunderstorms, accompanied by small hail, will taper off this evening.

In the greater Toronto area wet snow is expected to develop early this evening then end after midnight. Northern portions of the Toronto region can expect 2 to 4 cm, with little or no snow accumulation expected over southern sections of the city.

Late this evening there will be the risk for some freezing rain in a swath from Southern Lake Huron to Niagara, especially over higher elevations.

Locally hazardous road conditions can be expected in the precipitation this evening as temperatures fall to nearOr just below freezing in many locales. In addition, poor visibilities can be expected in bursts of heavier snow.